Not sure if the OP knows if the priority status is apparent if the OP does online check-in, that is, if the online check-in works:
To be sure, VX check-in counter agents at LAX will specifically tell you that you have priority for Main Cabin Select and First Class passengers through security if you do a manual airport check-in. The "Priority" label should be printed on your boarding pass if you collect the pass at airport check-in.